Primer paso de la investigacion. Se aportan el .apk, las carpetas con el apk extraido y el apk descompilado. El archivo API_DOCUMENTATION.md es un archivo donde se anotaran los descubrimientos del funcionamiento de la API, y los .py son scripts para probar la funcionalidad de la API con los métodos que vayamos encontrando. Finalmente, los archivos .js son scripts de Frida para extraer informacion de la APP durante la ejecucion.

apk_decompiled/sources/kotlin/io/TextStreamsKt.java

@@ -0,0 +1,201 @@
+package kotlin.io;
+
+import java.io.BufferedReader;
+import java.io.BufferedWriter;
+import java.io.InputStream;
+import java.io.Reader;
+import java.io.StringReader;
+import java.io.StringWriter;
+import java.io.Writer;
+import java.net.URL;
+import java.nio.charset.Charset;
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.List;
+import kotlin.Metadata;
+import kotlin.Unit;
+import kotlin.internal.InlineOnly;
+import kotlin.internal.PlatformImplementationsKt;
+import kotlin.jvm.JvmName;
+import kotlin.jvm.functions.Function1;
+import kotlin.jvm.internal.InlineMarker;
+import kotlin.jvm.internal.Intrinsics;
+import kotlin.jvm.internal.SourceDebugExtension;
+import kotlin.sequences.Sequence;
+import kotlin.sequences.SequencesKt;
+import kotlin.text.Charsets;
+
+@Metadata(d1 = {"\u0000X\n\u0000\n\u0002\u0018\u0002\n\u0002\u0018\u0002\n\u0000\n\u0002\u0010\b\n\u0002\u0018\u0002\n\u0002\u0018\u0002\n\u0000\n\u0002\u0010\t\n\u0002\b\u0002\n\u0002\u0010\u0002\n\u0000\n\u0002\u0018\u0002\n\u0002\u0010\u000e\n\u0000\n\u0002\u0018\u0002\n\u0000\n\u0002\u0010\u0012\n\u0002\u0018\u0002\n\u0000\n\u0002\u0010 \n\u0002\b\u0002\n\u0002\u0018\u0002\n\u0000\n\u0002\u0018\u0002\n\u0002\b\u0005\u001a\u0017\u0010\u0000\u001a\u00020\u0001*\u00020\u00022\b\b\u0002\u0010\u0003\u001a\u00020\u0004H\u0087\b\u001a\u0017\u0010\u0000\u001a\u00020\u0005*\u00020\u00062\b\b\u0002\u0010\u0003\u001a\u00020\u0004H\u0087\b\u001a\u001c\u0010\u0007\u001a\u00020\b*\u00020\u00022\u0006\u0010\t\u001a\u00020\u00062\b\b\u0002\u0010\u0003\u001a\u00020\u0004\u001a\u001e\u0010\n\u001a\u00020\u000b*\u00020\u00022\u0012\u0010\f\u001a\u000e\u0012\u0004\u0012\u00020\u000e\u0012\u0004\u0012\u00020\u000b0\r\u001a\u0010\u0010\u000f\u001a\b\u0012\u0004\u0012\u00020\u000e0\u0010*\u00020\u0001\u001a\n\u0010\u0011\u001a\u00020\u0012*\u00020\u0013\u001a\u0010\u0010\u0014\u001a\b\u0012\u0004\u0012\u00020\u000e0\u0015*\u00020\u0002\u001a\n\u0010\u0016\u001a\u00020\u000e*\u00020\u0002\u001a\u0017\u0010\u0016\u001a\u00020\u000e*\u00020\u00132\b\b\u0002\u0010\u0017\u001a\u00020\u0018H\u0087\b\u001a\r\u0010\u0019\u001a\u00020\u001a*\u00020\u000eH\u0087\b\u001a5\u0010\u001b\u001a\u0002H\u001c\"\u0004\b\u0000\u0010\u001c*\u00020\u00022\u0018\u0010\u001d\u001a\u0014\u0012\n\u0012\b\u0012\u0004\u0012\u00020\u000e0\u0010\u0012\u0004\u0012\u0002H\u001c0\rH\u0086\bø\u0001\u0000¢\u0006\u0002\u0010\u001e\u0082\u0002\u0007\n\u0005\b\u009920\u0001¨\u0006\u001f"}, d2 = {"buffered", "Ljava/io/BufferedReader;", "Ljava/io/Reader;", "bufferSize", "", "Ljava/io/BufferedWriter;", "Ljava/io/Writer;", "copyTo", "", "out", "forEachLine", "", "action", "Lkotlin/Function1;", "", "lineSequence", "Lkotlin/sequences/Sequence;", "readBytes", "", "Ljava/net/URL;", "readLines", "", "readText", "charset", "Ljava/nio/charset/Charset;", "reader", "Ljava/io/StringReader;", "useLines", "T", "block", "(Ljava/io/Reader;Lkotlin/jvm/functions/Function1;)Ljava/lang/Object;", "kotlin-stdlib"}, k = 2, mv = {1, 9, 0}, xi = 48)
+@JvmName(name = "TextStreamsKt")
+@SourceDebugExtension({"SMAP\nReadWrite.kt\nKotlin\n*S Kotlin\n*F\n+ 1 ReadWrite.kt\nkotlin/io/TextStreamsKt\n+ 2 fake.kt\nkotlin/jvm/internal/FakeKt\n+ 3 _Sequences.kt\nkotlin/sequences/SequencesKt___SequencesKt\n*L\n1#1,151:1\n52#1:152\n1#2:153\n1#2:156\n1313#3,2:154\n*S KotlinDebug\n*F\n+ 1 ReadWrite.kt\nkotlin/io/TextStreamsKt\n*L\n33#1:152\n33#1:153\n33#1:154,2\n*E\n"})
+/* loaded from: classes3.dex */
+public final class TextStreamsKt {
+    @InlineOnly
+    private static final BufferedReader buffered(Reader reader, int i) {
+        Intrinsics.checkNotNullParameter(reader, "<this>");
+        return reader instanceof BufferedReader ? (BufferedReader) reader : new BufferedReader(reader, i);
+    }
+
+    public static /* synthetic */ BufferedReader buffered$default(Reader reader, int i, int i4, Object obj) {
+        if ((i4 & 1) != 0) {
+            i = 8192;
+        }
+        Intrinsics.checkNotNullParameter(reader, "<this>");
+        return reader instanceof BufferedReader ? (BufferedReader) reader : new BufferedReader(reader, i);
+    }
+
+    public static final long copyTo(Reader reader, Writer out, int i) {
+        Intrinsics.checkNotNullParameter(reader, "<this>");
+        Intrinsics.checkNotNullParameter(out, "out");
+        char[] cArr = new char[i];
+        int read = reader.read(cArr);
+        long j4 = 0;
+        while (read >= 0) {
+            out.write(cArr, 0, read);
+            j4 += read;
+            read = reader.read(cArr);
+        }
+        return j4;
+    }
+
+    public static /* synthetic */ long copyTo$default(Reader reader, Writer writer, int i, int i4, Object obj) {
+        if ((i4 & 2) != 0) {
+            i = 8192;
+        }
+        return copyTo(reader, writer, i);
+    }
+
+    public static final void forEachLine(Reader reader, Function1<? super String, Unit> action) {
+        Intrinsics.checkNotNullParameter(reader, "<this>");
+        Intrinsics.checkNotNullParameter(action, "action");
+        BufferedReader bufferedReader = reader instanceof BufferedReader ? (BufferedReader) reader : new BufferedReader(reader, 8192);
+        try {
+            Iterator<String> it = lineSequence(bufferedReader).iterator();
+            while (it.hasNext()) {
+                action.invoke(it.next());
+            }
+            Unit unit = Unit.INSTANCE;
+            CloseableKt.closeFinally(bufferedReader, null);
+        } finally {
+        }
+    }
+
+    public static final Sequence<String> lineSequence(BufferedReader bufferedReader) {
+        Intrinsics.checkNotNullParameter(bufferedReader, "<this>");
+        return SequencesKt.constrainOnce(new LinesSequence(bufferedReader));
+    }
+
+    public static final byte[] readBytes(URL url) {
+        Intrinsics.checkNotNullParameter(url, "<this>");
+        InputStream openStream = url.openStream();
+        try {
+            Intrinsics.checkNotNull(openStream);
+            byte[] readBytes = ByteStreamsKt.readBytes(openStream);
+            CloseableKt.closeFinally(openStream, null);
+            return readBytes;
+        } finally {
+        }
+    }
+
+    public static final List<String> readLines(Reader reader) {
+        Intrinsics.checkNotNullParameter(reader, "<this>");
+        final ArrayList arrayList = new ArrayList();
+        forEachLine(reader, new Function1<String, Unit>() { // from class: kotlin.io.TextStreamsKt$readLines$1
+            /* JADX WARN: 'super' call moved to the top of the method (can break code semantics) */
+            {
+                super(1);
+            }
+
+            @Override // kotlin.jvm.functions.Function1
+            public /* bridge */ /* synthetic */ Unit invoke(String str) {
+                invoke2(str);
+                return Unit.INSTANCE;
+            }
+
+            /* renamed from: invoke, reason: avoid collision after fix types in other method */
+            public final void invoke2(String it) {
+                Intrinsics.checkNotNullParameter(it, "it");
+                arrayList.add(it);
+            }
+        });
+        return arrayList;
+    }
+
+    public static final String readText(Reader reader) {
+        Intrinsics.checkNotNullParameter(reader, "<this>");
+        StringWriter stringWriter = new StringWriter();
+        copyTo$default(reader, stringWriter, 0, 2, null);
+        String stringWriter2 = stringWriter.toString();
+        Intrinsics.checkNotNullExpressionValue(stringWriter2, "toString(...)");
+        return stringWriter2;
+    }
+
+    public static /* synthetic */ String readText$default(URL url, Charset charset, int i, Object obj) {
+        if ((i & 1) != 0) {
+            charset = Charsets.UTF_8;
+        }
+        Intrinsics.checkNotNullParameter(url, "<this>");
+        Intrinsics.checkNotNullParameter(charset, "charset");
+        return new String(readBytes(url), charset);
+    }
+
+    @InlineOnly
+    private static final StringReader reader(String str) {
+        Intrinsics.checkNotNullParameter(str, "<this>");
+        return new StringReader(str);
+    }
+
+    public static final <T> T useLines(Reader reader, Function1<? super Sequence<String>, ? extends T> block) {
+        Intrinsics.checkNotNullParameter(reader, "<this>");
+        Intrinsics.checkNotNullParameter(block, "block");
+        BufferedReader bufferedReader = reader instanceof BufferedReader ? (BufferedReader) reader : new BufferedReader(reader, 8192);
+        try {
+            T invoke = block.invoke(lineSequence(bufferedReader));
+            InlineMarker.finallyStart(1);
+            if (PlatformImplementationsKt.apiVersionIsAtLeast(1, 1, 0)) {
+                CloseableKt.closeFinally(bufferedReader, null);
+            } else {
+                bufferedReader.close();
+            }
+            InlineMarker.finallyEnd(1);
+            return invoke;
+        } catch (Throwable th) {
+            try {
+                throw th;
+            } catch (Throwable th2) {
+                InlineMarker.finallyStart(1);
+                if (PlatformImplementationsKt.apiVersionIsAtLeast(1, 1, 0)) {
+                    CloseableKt.closeFinally(bufferedReader, th);
+                } else {
+                    try {
+                        bufferedReader.close();
+                    } catch (Throwable unused) {
+                    }
+                }
+                InlineMarker.finallyEnd(1);
+                throw th2;
+            }
+        }
+    }
+
+    @InlineOnly
+    private static final BufferedWriter buffered(Writer writer, int i) {
+        Intrinsics.checkNotNullParameter(writer, "<this>");
+        return writer instanceof BufferedWriter ? (BufferedWriter) writer : new BufferedWriter(writer, i);
+    }
+
+    public static /* synthetic */ BufferedWriter buffered$default(Writer writer, int i, int i4, Object obj) {
+        if ((i4 & 1) != 0) {
+            i = 8192;
+        }
+        Intrinsics.checkNotNullParameter(writer, "<this>");
+        return writer instanceof BufferedWriter ? (BufferedWriter) writer : new BufferedWriter(writer, i);
+    }
+
+    @InlineOnly
+    private static final String readText(URL url, Charset charset) {
+        Intrinsics.checkNotNullParameter(url, "<this>");
+        Intrinsics.checkNotNullParameter(charset, "charset");
+        return new String(readBytes(url), charset);
+    }
+}